Plasma processing apparatus and method for adjusting plasma density distribution

Abstract

In the plasma processing apparatus 1 , microwaves supplied from a coaxial waveguide 30 are introduced into a processing container 2 via a wavelength-shortening plate 25 , a process gas is plasmatized in the processing container 2 , and a substrate W is processed using the plasma. In the plasma processing apparatus 1 , a dielectric member 45 is disposed at a connecting area between the coaxial waveguide 30 and the wavelength-shortening plate 25 . Inside an outer conductor 32 of the coaxial waveguide 30 , the dielectric member 45 is disposed to surround a part of a circumference of an inner conductor 31 of the coaxial waveguide 30 , and is disposed at any position around the circumference of the inner conductor 31.

1. A plasma processing apparatus in which microwaves supplied from a coaxial waveguide having an inner conductor and an outer conductor are introduced into a processing container via a wavelength-shortening plate, a process gas is plasmatized in the processing container, and a substrate is processed using the plasma,
 wherein a dielectric member is disposed on the wavelength-shortening plate at a connecting area between the coaxial waveguide and the wavelength-shortening plate; and 
 the dielectric member on the wavelength-shortening plate is disposed to surround a part of a circumference of the inner conductor and can be moved to and disposed at any position around the circumference of the inner conductor. 
 
     
     
       2. The plasma processing apparatus of  claim 1 , wherein the dielectric member is freely rotatable around the inner conductor. 
     
     
       3. The plasma processing apparatus of  claim 2 , wherein the outer conductor further comprises a ring which is rotatable, and the dielectric member is attached to an inner surface of the ring. 
     
     
       4. The plasma processing apparatus of  claim 1 , wherein the dielectric member is ceramic or Teflon. 
     
     
       5. The plasma processing apparatus of  claim 4 , wherein the ceramic is one of Al 2 O 3 , quartz, and AlN. 
     
     
       6. The plasma processing apparatus of  claim 1 , wherein the dielectric member and the wavelength-shortening plate are integrally formed. 
     
     
       7. The plasma processing apparatus of  claim 1 , wherein the dielectric member and the wavelength-shortening plate are formed of the same material. 
     
     
       8. The plasma processing apparatus of  claim 1 , wherein a plurality of dielectric members are disposed on the wavelength-shortening plate. 
     
     
       9. A plasma processing apparatus in which microwaves supplied from a coaxial waveguide having an inner conductor and an outer conductor are introduced into a processing container via a wavelength-shortening plate, a process gas is plasmatized in the processing container, and a substrate is processed using the plasma,
 wherein a dielectric member is disposed on the wavelength-shortening plate at a connecting area between the coaxial waveguide and the wavelength-shortening plate; and 
 the dielectric member on the wavelength-shortening plate is disposed to surround a part of a circumference of the inner conductor, and can be moved to and disposed at any position around the circumference of the inner conductor, 
 wherein the plasma density is lower at the area corresponding to the dielectric member than at the area not corresponding to the member. 
 
     
     
       10. A plasma processing apparatus comprising:
 a processing container into which a wafer is carried;
 a gas path through which a gas is supplied into the processing container; 
 a transmission window which is air-tightly disposed in an opening of an upper portion of the processing container using a sealing member and transmits microwaves; 
 a planar antenna member which is disposed above the transmission window; 
 a wavelength-shortening plate which is disposed on an upper surface of the planar antenna member and shortens the wavelength of the microwaves; 
 a conductive cover which covers the wavelength-shortening plate; 
 a coaxial waveguide which is connected to the cover and has an inner conductor and an outer conductor: and 
 a dielectric member which surrounds a part of the circumference of the inner conductor, and is disposed on a part of the wavelength-shortening plate at a connecting area between the coaxial waveguide and the wavelength-shortening plate and can be moved to and disposed at any position along and around a circumference of the inner conductor. 
 
 
     
     
       11. The plasma processing apparatus of  claim 10 , wherein the dielectric member is ceramic or Teflon. 
     
     
       12. The plasma processing apparatus of  claim 11 , wherein the ceramic is one of Al 2 O 3 , quartz, and AlN. 
     
     
       13. The plasma processing apparatus of  claim 10 , wherein the dielectric member and the wavelength-shortening plate are integrally formed. 
     
     
       14. The plasma processing apparatus of  claim 10 , wherein the dielectric member and the wavelength-shortening plate are formed of the same material. 
     
     
       15. The plasma processing apparatus of  claim 10 , wherein a plurality of dielectric members are disposed on the wavelength-shortening plate. 
     
     
       16. The plasma processing apparatus of  claim 10 , wherein a protrusion is formed at the center of an upper surface of the wavelength-shortening plate such that the protrusion extends upward from a lower end of the outer conductor. 
     
     
       17. The plasma processing apparatus of  claim 16 , wherein the protrusion is formed in a truncated cone shape.